Experience the extraordinary 72 hours that culminated in world war two. Channel 5 documentary series presented by jj chalmers and raksha dave.   on friday 1st september 1939, germany invaded poland and the clock started ticking. On sunday morning, britain had declared war. Learn about the three days that led up to the second world war and changed the world forever.  presenters jj chalmers and raksha dave visit key locations, meet historians and unearth startling archive material. They have a go at putting up blackouts, trying some basic army training and preparing for air raids – and meet the descendants of those involved, who share their relatives’ spellbinding stories.